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Old 04-24-2022, 02:28 PM   #1
stevemitchell
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City: Seattle
Vessel Name: Aruna
Vessel Model: Kristen Yachts 50 Pilot House
Join Date: Sep 2018
Posts: 541
Problems changing Kohler 13.5CCOZ output from 120 to 240

I have a Kohler 11CCFOZ/13.5CCOZ marine generator that I am struggling with changing from 120v to 240v. The reason I say 11CCFOZ/13.5CCOZ is that the generator was mis-labeled when the boat was built (according to the previous owner) - the 11CCFOZ is a 50hz unit, and the 13.5CCOZ is 60hz. At some point the unit was "converted" to 60hz since the boat has always been in the US and used on 60hz power. I mention this only in case there is some history or limitation with the 11CCFOZ, but I don't think there is.

The unit is currently producing 120v AC @ 60hz and can pump out close to 100 amps of power. It also has a three pole, with only one pole being used for the hot L1, 100 amp output breaker that looks original.

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The specs say that this generator can output 120 or 240 volts, single phase. I'm trying to use it with a split phase set of inverters and need two different legs of 120v @ 60hz to each of them.

I have a neighbor with what appears to be the same exact generator that is already setup this way. I have confirmed the wiring on his matches the wiring I switched mine to.

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From the Installation and Operations manual, this is how the voltage connections are right now to produce 120v AC (picture above).

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I have tried wiring it up like the above diagram, also from the operations and installation manual. This should give me two separate legs of 120v, but it doesn't. Instead, I get a pulsing amount of voltage ranging from 60v-130v (or sometimes higher or lower) depending on how I adjust the voltage regulator.

I've followed the process to adjust the voltage regulator several times, and never seem to be able to stabilize the voltage on either leg. I can see the lights on the voltage regulator and on the control board pulsing as the voltage goes up and down.

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The unit has the Powerboost voltage regulator, board B-258296, and when I flip it back to 120v it works just fine (after a quick adjustment).

I'm trying to determine whether it is even possible to produce 240v out of this set. I would think it would be since most all generators I've ever set hands on use a similar setup where you can convert them between 50/60hz and 120/240 volts with wiring and some patience.

I'm at a loss as to why I can't do it with this model, and am beginning to think there is a board or component that limits this unit to 120v, or I am being super stupid and forgot to do something.
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m/v Aruna
50 Kristen Yachts Pilothouse
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